All-Intra (ALL-I)

What it means

Video codecs can save space in two ways: by compressing each frame like a photo, and by only storing what changes between frames. All-Intra uses only the first method. Every frame is a complete keyframe that can be decoded without looking at its neighbors.

That makes ALL-I files simple for computers to work with. Jumping to any frame, scrubbing a timeline or cutting at an exact point is quick, because the software never has to rebuild a frame from a chain of predictions. ProRes and many cinema codecs work this way.

The opposite approach is Long GOP, which most action cameras and phones use to keep files small.

How it works in practice

Some mirrorless and cinema cameras offer both ALL-I and Long GOP versions of the same codec. Editors who work on long projects, heavy grading or effects often prefer ALL-I because playback stays responsive and every frame holds full quality on its own.

Action cameras rarely offer it, since an ALL-I stream needs a much higher Bitrate for the same quality, which means bigger files, faster cards and more heat. When editing action footage feels slow, transcoding to an intra-frame format like ProRes is the usual fix.

ALL-I also handles very fast motion gracefully, because no frame depends on a prediction that the motion broke.

What to watch out for

Bigger is not automatically better. An ALL-I file at a low bitrate can look worse than a well-encoded Long GOP file, because each frame gets less data. Compare quality at realistic bitrates rather than assuming one method wins.

Storage and card speed matter. Recording ALL-I at high resolution can exceed what older memory cards sustain, leading to dropped frames or stopped recording. Check the camera manual for the card class required for each mode before relying on it for important footage. A short test recording at the highest setting tells you more than any spec sheet.